Various therapies, examinations, procedures and other processes have conventionally been performed in which a medical apparatus, such as a catheter, is inserted into a variety of human tubular organs and body tissues such as blood vessels, the gastrointestinal tract, the urinary tract, and so on. Recently, therapies and other procedures in which a specified reagent is injected into a lesion in body tissue using a reagent injection device, such as a reagent injection catheter, are also being carried out (e.g., Japanese Patent Laid-open No. 2001-299927).
These reagent injection devices used to inject reagents into lesions, etc., have a structure in which a needle-like tubular body is movably inserted into a main tube. Also, the needle-like tubular body generally has a sharp needle at its tip. Additionally, the tubular body has an inner hole through which a specified reagent is passed. In a reagent injection device having this structure, the needle of the needle-like tubular body projects out of the main tube that has been inserted into a blood vessel, in order to puncture the target lesion in body tissue and thereby inject a specified reagent into the lesion through the inner hole provided in the needle-like tubular body.
In the above, some reagent injection devices having this structure are designed with two guide wires in such a way that the load from the reactive force generated by a needle-puncturing action is received by the two guide wires (e.g., Japanese Patent Laid-open No. 2003-250899).
To be specific, the reagent injection device has one guide wire extending out of the main tube (catheter main body) through an opening provided at the tip of the main tube. The other guide wire extends to the outside through an opening provided in the tube wall on a side of the main tube. In this reagent injection device, when the main tube is inserted into a blood vessel dividing into two branches, for example, the guide wire extending out of the opening at the tip of the main tube is inserted into one branch vessel, while the other guide wire extending out of the opening on a side of the main tube is inserted into the other branch vessel. At this time, the balloon attached externally to the main tube is inflated. In this condition, the needle of the needle-like tubular body is projected out of the main tube and caused to puncture the target lesion in body tissue.
As explained above, the reagent injection device allows the reactive force generated when the needle punctures the target body tissue to be received by the two guide wires inserted separately into the two branch vessels. The balloon also prevents displacement of the main tube inside the blood vessel. These actions ultimately prevent rotation of the main tube about its axis center, which rotation could otherwise occur due to the reactive force generated when the needle punctures the target body tissue and also due to other forces resulting from a kink of the needle-like tubular body, and so on. Consequently, the needle can reliably and smoothly reach a desired depth in the target body tissue. At the same time, the puncturing location of the needle in the body tissue can be maintained in a stable manner.